AIGame/AIClient/Packages/com.unity.pipeline/.claude/skills/unity-pipeline/SKILL.md

name, description

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description

unity-pipeline

Drive a running Unity Editor or development Player from the command line via the unity-pipeline package — install the package, keep the editor ticking while unfocused, run the edit→recompile→run_tests loop, evaluate C#, and code-reload files at runtime. Use when an agent needs to control a live Unity instance, automate Unity tests, recompile scripts headlessly, or apply runtime reloads. Assumes the `unity` CLI is on PATH.

Unity Pipeline (agent control)

Invoke commands with unity command <name> [args]. Run unity command with no name to list what an instance exposes. Two servers exist: Editor (7800-7849, auto-starts with the editor) and Runtime (7900-7949, only in a dev Player build). See the package README.md "Commands" reference for the full list and parameters.

1. Install & verify

unity pipeline install            # install into current project (or --project-path)
unity pipeline list               # confirm the editor instance + server are reachable
unity command editor_status       # confirm the editor server answers

2. Autonomous edit loop (Editor)

This is the core agent workflow: keep the editor alive, change code, recompile, test.

# 1. Keep the editor ticking even when unfocused/minimized. REQUIRED before headless work —
#    Unity otherwise throttles or stalls update/compile when it isn't the active app.
unity command set_autotick --enable true

# 2. Edit C# source files on disk normally.

# 3. Recompile (async: triggers a domain reload, then poll until done).
unity command recompile
unity command recompile_status    # repeat until "completed" or "up_to_date"
#   Tolerate connection errors while the domain reload is in flight — that is expected.
#   If recompile_status reports failed=true, read its "errors" array and fix before testing.

# 4. (Optional) List available tests without running them.
unity command list_tests --mode editor            # mode: all | editor | playmode

# 5. Run tests (filter to keep it fast).
unity command run_tests --mode editor --filter MyFixture.MyTest

run_tests modes: all | editor | playmode. filter_type: testName | assembly | category. For long runs use --async_tests true and poll unity command test_status (abort with unity command cancel_tests).

Known caveat: when any selected test fails, run_tests may surface an opaque result instead of the failure details. Re-run a narrower --filter, or inspect the editor's Test Runner / logs to get the real failure.

Reading exit codes. They separate "rewrite the invocation" from "the Editor failed", which is the distinction this loop depends on:

Exit	Meaning	What to do
2	Bad arguments — a misspelled flag, a wrong type, too many positionals. Nothing ran.	Fix the command line and retry. The error names the problem and often suggests the right flag.
6	The command ran and failed, or the Editor could not service it.	Read the error; retrying the same invocation will not help.

Do not retry an exit 2 unchanged, and do not rewrite a command line on an exit 6.

3. Runtime code reload

Change gameplay code in a running game with no domain reload. The game must be live: enter Editor Play Mode (unity command editor_play) or run a dev Player. A The runtime Pipeline driver (enabled via Project Settings > Pipeline > Runtime) auto-discovers tagged methods on Awake (no manual registration). Mono only — Editor Play Mode and Mono desktop dev builds, not IL2CPP. The token is auto-injected for local requests.

reload_file

Edit the method body directly; no separate file, no boilerplate.

1. Tag the method [CodeReload] on the MonoBehaviour.
2. Edit its body on disk.
3. Apply (re-run to iterate):

   unity command reload_file --filename Assets/Spinner.cs
   

   Add --pdb to make it debuggable — emits a portable PDB mapped to your source so breakpoints in the original file bind (attach the IDE + enable Editor Attaching; compiles unoptimized):

   unity command reload_file --filename Assets/Spinner.cs --pdb
   

Constraints: void instance methods only; public members only; debugging requires --pdb (the default emits no symbols).

unity command codereload_status shows active overrides. reload_file options: --timeout <ms> (default 30000), --assemblyDir <dir> (persist DLLs instead of in-memory); cleanup_codereload --assemblyDir <dir> clears old DLLs.

4. Bulk construction: run_script (the builder pattern)

For bulk work — creating many objects, wiring fields, generating content — put the code in a versioned project script and run a named static entry point with run_script. No domain reload, no code carried through the protocol; iterating costs an in-memory compile (< ~2s), not a 15–20s recompile.

# 1. Write the builder OUTSIDE Assets/ (so the write triggers no asset import / domain reload),
#    e.g. AgentScripts/Build.cs:  public static class Build { public static int All() { ... } }
# 2. Run it — relative paths resolve against the project root (the parent of Assets/):
unity command run_script --file AgentScripts/Build.cs --entry Build.All
# 3. Iterate: edit the file, re-run. Useful extras:
unity command run_script --file AgentScripts/Build.cs --dry_run true   # compile-only check: diagnostics, nothing loaded or executed
unity command run_script --file AgentScripts/Build.cs --entry Build.All --args '[3, "Green"]'

Rules of thumb:

• Code goes in files on disk via run_script; eval is for genuinely ad-hoc one-liners. Never ship multi-line escaped C# strings through eval — write the file, run the entry.
• Compiles see the project's active editor defines (UNITY_EDITOR, version/platform symbols); --defines appends extra symbols on top.
• Entry points may be async Task/Task<T> — they are awaited asynchronously (the editor keeps pumping, so awaits resuming on Unity's context work naturally) and Task<T>.Result is returned. The wait is bounded by timeout_ms; on expiry the task keeps running detached.
• Runtime exceptions come back with file:line mapped to your source (a source-mapped PDB is always emitted for executing runs; they compile unoptimized).
• --mode hotpatch instead applies [CodeReload] in-place method replacements (delegates to reload_file); entry/args/dry_run are rejected there and references/defines don't apply.

5. Quick C# eval (Runtime)

For genuinely ad-hoc one-liners only — anything longer belongs in a file run via run_script.

unity command eval "return 2 + 2;"
# Or evaluate a .cs file on disk (contents run through the same path):
unity command eval_file Assets/Scratch.cs

5. Project audit (Editor)

Static-analysis scan via Project Auditor, producing a CSV of issues to fix. Trigger, poll, read.

unity command audit                              # optional: --categories Code,ProjectSetting --output my.csv
unity command audit_status                       # repeat until terminal status

audit_status is terminal on completed (with csvPath + issueCount), failed, unavailable, or interrupted (a domain reload killed the scan — just re-run audit). Polling stays responsive while a Code-category scan compiles assemblies and holds the main thread. One scan at a time: a second audit returns busy. There is no cancel — stop polling to abandon a scan.

CSV columns: Category, Severity, Areas, Description, RelativePath, Line, DescriptorId, Recommendation (diagnostics only, so every row is something to fix; Recommendation says how).

Requires Project Auditor plus its rules. unavailable means the Editor has no Project Auditor, or it has no analysis rules — in a built-in-module Editor the rules live in the separate com.unity.project-auditor-rules package (unity command package_add --identifier com.unity.project-auditor-rules --confirm true). Read the message field; the command never reports an empty completed scan that would look like a clean project.

Gotchas

• set_autotick first. Without it, recompile and tests can hang while the editor is unfocused. The package's watchdog relies on the tick loop staying alive.
• A stuck command may mean a modal dialog is open, not a hang — a dialog blocks the main thread until dismissed. If a command runs long, check unity command editor_status (answers instantly even when blocked); status: "blocked_by_dialog" means stop retrying and tell the human what's blocking (its dialog.title/message/buttons) — it can't be clicked over CLI.
• Code reload needs the game running. reload_file applies to a live game — enter Editor Play Mode (unity command editor_play) first, or run a dev Player.
• Player-only commands need a dev Player. log, set_timescale, runtime_status, etc. hit the Runtime server, which does not run in the Editor.
• Async commands poll. recompile→recompile_status, run_tests --async_tests→ test_status. Never assume completion from the trigger call's response.
• Target a specific instance with --instance host:port or --project-path <path> when more than one is running.